1. Field of the Invention
The present invention relates to a nut with a cover, which is adapted to be secured to, for instance, a floor panel of a motor vehicle by means of welding or clinching.
2. Description of the Prior Art
When various members are to be fastened onto, for instance, a floor panel of a motor vehicle by means of bolts, nuts such as weld nuts and pierce nuts are secured to the panel by welding or clinching. A thick coating such as a coating of vinyl chloride sol, is applied on the panel for prevention of rust, after securing the nuts to the panel, and in this case, there is a risk that the coating may also be applied to the internal threads of the nuts. In order to avoid this risk, it has hitherto been known to mask the nuts before the coating of vinyl chloride is effected. However, if a large number of nuts are used for the panel, the masking process becomes very troublesome. To cope with this problem, the present inventors have previously proposed a nut with cover, in Japanese Utility Model Laid-Open No. 115010/1986, in which a cover of synthetic resin is injection-molded in the internally threaded portion of a nut so as to prevent any penetration of coating into the internally threaded portion. However, it has been found that this covered nut would encounter a difficulty in actual use. That is, when bolts are screwed into the nuts, the material forming the covers is pushed out from the nut by the leading end of the bolts and the covers are scattered in every direction around the motor vehicle assembly line.